1. Field of the Invention
Embodiments of the present invention generally relate to apparatus and method for supporting a substrate during transfer operations. Particular, embodiments of the present invention relate to apparatus and method for supporting and transferring large area substrate in a vacuum condition.
2. Background
Large area substrates are generally used in manufacturing solar panels, flat panel displays—such as active matrix, or thin film transistor (TFT) displays, liquid crystal displays (LCD), plasma displays, and the like.
With the marketplace's acceptance of solar technology and flat panel technology, the demand for larger solar panels or flat display panels, increased production, and lower manufacturing costs have driven equipment manufacturers to develop new systems that accommodate larger size substrates for solar panel and flat panel display fabricators.
Large area substrate processing is typically performed by subjecting a substrate to a plurality of sequential processes to create devices, conductors, and insulators on the substrate. Each of these processes is generally performed in a process chamber configured to perform one or more steps of the production process. In order to efficiently complete the entire sequence of processing steps, a number of process chambers are typically coupled to a central transfer chamber that houses a robot to facilitate transfer of the substrate between the process chambers. Processing platforms having this configuration are generally known as cluster tools. Such cluster tools for glass substrate processing are available from AKT, Inc., a wholly-owned subsidiary of Applied Materials, Inc., of Santa Clara, Calif.
As large area substrates increase in size, the manufacturing equipment for handling and processing these substrates must become larger as well. The increased size of substrate handling equipment, such as the transfer robot mentioned above, has created a number of technical challenges that must be overcome in order to maintain accurate substrate transfer. For example, one transfer robot used to handle flat panel substrates has a series of cantilevered end effectors supported from a wrist that support that underside of the substrate. A plurality of pads are generally attached to the end effectors for direct contact with the substrates. The pads subject to wear and need to be replaced periodically. Replacing the pads takes a relative long time due to the relatively large number of the pads and the entire cluster tool needs to be shut down during pad replacement. As a result, the cost of ownership increases due to the long period required by replacing pads on the end effector.
Therefore, there is a need for an end effector and end effector pads with reduced maintenance requirement to accommodate large substrates